The top ten islands is almost complete (not in the mandelbrotian sense). I added a new list of coastline bounty in the wiki (11-30 largest islands) http://wiki.openstreetmap.org/wiki/WikiProject_Philippines/Coastline_Corrections#Priorities
Please edit the status as you start working on each island. Note that some have a 99% status already, but, it is good for other eyeballs to have a look and comment on the actual %age and status. On Wed, Jul 7, 2010 at 2:03 AM, Eugene Alvin Villar <sea...@gmail.com> wrote: > On Tue, Jul 6, 2010 at 2:42 PM, Jim Morgan <j...@datalude.com> wrote: >> >> Eugene Alvin Villar wrote, On Tuesday, 06 July, 2010 11:57 AM: >> > To clarify things, the sawtooth detection script is quite naive. It >> > simply detects if there are at three or more series of nodes where each >> > pair of adjacent nodes have the same latitude or longitude. This will >> > also detect any three linear nodes that all have the same latitude or >> > longitude like this: o----o----o >> >> There are a number of cases where a near-straight line is acceptable. >> Maybe it would be better -- and I'm not sure if this is possible -- to >> examine, say, a series of three nodes. It would check if the first two have >> the same lat or long. If they have the same lat, then the second and third >> points would need the same long; if they have the same long, then the second >> and third points would need the same lat. Then you'd be correctly >> identifying the step-fashion jaggies, rather than straight lines. >> >> >> To increase certainty, you could make this a series of four, or five >> points. Again I don't know if this is possible or plausible, but it would >> seem like a better pattern to look for. Not sure if the formatting will come >> through but .... >> >> >> p1 |_____ p2 >> | >> | >> p3 |______ p4 >> | > > I intentionally wanted to detect collinear nodes since I wasn't sure if the > original SRTM-based data have those collinear nodes or not. > > In any case, the script detects sawtooth coasts if the latitude or the > longitude is *exactly* the same, right down to the 7th decimal place (which > translates to an accuracy of about 1 cm). So if there are a series of > coastline nodes that have the same latitude or longitude for each adjacent > pair of nodes, then they are most likely generated from raster data, like > SRTM. I don't think Mother Nature created coasts that follow latitudes and > longitudes. :-) > > > _______________________________________________ > talk-ph mailing list > talk-ph@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-ph > > -- cheers, maning ------------------------------------------------------ "Freedom is still the most radical idea of all" -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ ------------------------------------------------------ _______________________________________________ talk-ph mailing list talk-ph@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ph